The present invention relates generally to aircraft, and, more specifically, to windows therein.
In the typical commercial aircraft, numerous windows are distributed along both sides of the fuselage between the cockpit and tail. Each window includes a frame suitably mounted in a corresponding aperture in the external skin of the aircraft, and each frame securely mounts therein a corresponding window pane.
Typical aircraft skins are made of high strength metal, such as aluminum, and the typical window frame is also made of high strength metal.
Since aircraft weight directly affects aircraft efficiency during flight, aircraft are continually improved for reducing weight while providing sufficient strength for the various aircraft components to enjoy long service life during commercial operation.
US Patent Application Publication 2008/0169380A1 discloses a non-metal composite window frame having carbon fiber laminates manufactured by compression molding for reducing weight while providing high strength.
U.S. Pat. No. 7,988,094 discloses a corresponding titanium erosion shield for protecting the composite window frame during aircraft flight.
The composite window frame and metal erosion shield are initially separately manufactured and then bonded together to form the finished assembly for mounting window panes in the aircraft.
The assembly process includes many steps to accurately position the shield in the frame and ensure maximum strength thereof.
In one development process, these steps include machining of the composite frame to accept the titanium erosion shield ring and drilling holes in the frame. The composite material and the titanium ring then go through a secondary bonding step where the operator adds a secondary adhesive or sealant, such as rubber, to glue or adhere the titanium ring onto the window frame.
After completion of the secondary bonding step, the glued composite material and titanium ring undergo a second cooking/pressing, following which the assembly is removed from the molding tool and cleaned to remove stray sealant.
Following the clean up step, the assembly is inspected around the areas containing sealant, and any voids thereof are sealed. The window frame with titanium shield goes through another inspection step to ensure that the sealant is not excessive.
After ensuring acceptable bonding of the shield to the frame, the window frame is painted, and then finally inspected for delivery to the customer.
The final composite window frame and attached shield have reduced weight and high strength attributable to the elaborate process of manufacture, but with attendant manufacturing cost.
Accordingly, it is desired to provide an improved method of manufacture of an aircraft window frame for reducing cost while ensuring high strength with low weight.